This project will complete the development and evaluation of an epidural sensor to measure cerebrospinal fluid pressure around the brain. The total project consists of two interacting parts: (1) The microelectronics, electronics, and structural design, fabrication, and laboratory test will be carried out in the Solid State Research Laboratory of the Department of Electrical Engineering at The University of Texas at Austin; (2) The surgical procedures on test animals (mostly dogs) will be conducted at the Neurosurgery Department of The University of Texas Health Center in San Antonio under the direction of Dr. James Storey. This proposal covers only Part 1. One design now exists, works, and shows that the method of pressure measurement works. The first task on this grant will be to fabricate the redesigned structure to reduce the volume to approximately 1.5 cm3. Parts, assembly, and system tests on the electronics can be executed in the laboratory without the use of animals. As "tested" units and systems become available, the neurosurgery staff plan to evaluate the units and systems for clinical application through the use of test animals. The total goal will be to achieve sufficient experience, confidence, hardware, and data to support the case for trying the devices on appropriate human subjects. Part 1 consists of electrical design, fabrication, and test. Part 1 includes supplying the electronic systems for execution of the neurosurgical studies in Part 2.